Researchers Create Sea Urchin-Inspired Smart Material

The research, published in the journal *Nature*, was led by Professor Lu Jian, Dean of the College of Engineering at City University of Hong Kong. The team's work focused on the long-spined sea urchin, *Diadema setosum*, uncovering that its porous ceramic spines can generate a measurable voltage signal from the movement of water. This electrical response is remarkably fast, occurring within tens of milliseconds, which is over a thousand times faster than the sea urchin's own visual perception. When a single drop of seawater lands on a spine, it can induce a transient potential of about 100 millivolts. Crucially, the researchers discovered this mechanoelectrical effect is an intrinsic property of the spine's physical microstructure, not a biological or neural function. This means the material itself is capable of converting mechanical force into an electrical signal, even without any living tissue present. Using an advanced 3D printing technique called vat photopolymerization, the team fabricated biomimetic polymer and ceramic materials that mimicked the sea urchin spine's gradient porous structure. These artificial structures showed a threefold increase in voltage output and an eightfold increase in signal amplitude compared to non-gradient structures, proving the importance of the specific architecture. The team has already constructed a prototype of a biomimetic metamaterial mechanoreceptor. This device can detect underwater flow direction and intensity in real-time without needing an external power source, opening up possibilities for next-generation smart sensing. Potential applications for this new smart material are vast and include marine environmental monitoring, intelligent underwater exploration, and even new types of biomedical devices. This breakthrough challenges the conventional view that natural porous structures are purely for mechanical support, revealing their latent sensing capabilities.